Memory provides one of the support infrastructures to modern computer and electronic devices. As memory capacity and density increase per unit of area, smaller devices have generally become more capable of complex and powerful processing, such as the processing of audio, video, graphics, and the like. Many such smaller devices exist as independent, hand-held devices, such as mobile phones, personal digital assistants (PDAs), and the like. Because most, if not all, hand-held devices operate using a battery to provide the primary device power, power management is a high priority in any hand-held device design process, including the design of memory that will be used in such devices.
FIG. 1 is a diagram illustrating a standard semiconductor device 10. The semiconductor device 10 is an integrated chip device containing dual processors, processors 100 and 101, and on-chip memory 102-105. When designing the semiconductor device 10, the various gates and components are often first planned in a computer-aided design environment. The mapping and lithography plans are generated before the semiconductor manufacturer begins actually fabricating the semiconductor device 10. One consideration important to the design is the physical footprint or coverage area within the semiconductor material for each component. This consideration influences the size and overall floor plan of the semiconductor device 10. A floor plan is generally considered the physical blueprint or total coverage area taken up by the combined components of the semiconductor device 10.
The semiconductor device 10 is powered by a battery 106. Thus, the semiconductor device 10 may be a variety of different, special purpose processing systems within a number of different devices, such as mobile phones, PDAs, handheld devices, or the like. Another consideration, as noted above, when designing the semiconductor device 10 is the power consumption traits of each embedded constituent component including the memories 102-105.
The power consumed by such embedded memories is typically measured as a combination of the dynamic or active power and the standby or static power. Standby/static power is generally considered the off-state current leakage that occurs even when the device is considered off. While static power used to be a problem in the hand-held or mobile industry, it has generally been controlled through the use of head switches and foot switches. Dynamic power, however, which is the power consumption based on an application's interaction with a memory, is still considered an area where power savings can be achieved. Because dynamic power relates to how a particular application accesses memory, careful tuning and control are often prompted in order to bring the power down.